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Öğe N-type InP Schottky diodes with organic thin layer: Electrical and interfacial properties(Journal of Vacuum Science & Technology B, 2010-03) Güllü, Ömer; Turut, AbdulmecitThe rectifying junction characteristics of methyl red (MR) organic film on n-type InP substrate have been studied. It has been observed that MR-based structure shows an excellent rectifying behavior and that the MR film increases the effective barrier height by influencing the space charge region of the n-type InP. The barrier height and ideality factor values for this structure have been obtained as 0.75 eV and 1.93 from the forward bias current-voltage characteristics, respectively. By using capacitance-voltage characteristics at 1 MHz, the barrier height and the carrier concentration values have been calculated as 0.93 eV and 5.13×1015 cm−3, respectively. The energy distributions of the interface states and their relaxation times have been determined from the forward bias capacitance-frequency and conductance-frequency characteristics. Moreover, it was seen that both the interface-state density and the relaxation time of the interface states decreased with bias voltage from experimental results.Öğe Batman ilinin doğal gaz ihtiyacının ve hava kirliliğini azaltmasının matematiksel yöntemlerle modellenmesi(Karabük Üniversitesi, 2009) Aydın, Hüseyin; Yaşar, Fevzi; Bezek Güre, ÖzlemÖğe Electrical analysis of organic dye based MIS Schottky contacts(Microelectronic Engineering, 2010-05-25) Güllü, Ömer; Turut, AbdulmecitIn this work, we prepared metal/interlayer/semiconductor (MIS) diodes by coating of an organic film onp-Si substrate. Metal(Al)/interlayer(Orange G@OG)/semiconductor(p-Si) MIS structure had a good recti-fying behavior. By using the forward-biasI–Vcharacteristics, the values of ideality factor (n) and barrierheight (BH) for the Al/OG/p-Si MIS diode were obtained as 1.73 and 0.77 eV, respectively. It was seen thatthe BH value of 0.77 eV calculated for the Al/OG/p-Si MIS diode was significantly larger than the value of0.50 eV of conventional Al/p-Si Schottky diodes. Modification of the potential barrier of Al/p-Si diode wasachieved by using thin interlayer of the OG organic material. This was attributed to the fact that the OGorganic interlayer increased the effective barrier height by influencing the space charge region of Si. Theinterface-state density of the MIS diode was found to vary from 2.79x1013to 5.80x1012eVx1cmx2.Öğe Electronic properties of the metal organic interlayer inorganic semiconductor sandwich device(Elsevier, 2010-03) Güllü, Ömer; Turut, Abdulmecit; Kılıçoğlu, TahsinIn this study, we prepared a Metal(Al)/Organic Interlayer(Congo Red=CR)/Inorganic Semiconductor (p-Si) (MIS) Schottky device formed by coating of an organic film on p-Si semiconductor wafer. The Al/CR/p-Si MIS device had a good rectifying behavior. By using the forward bias I–V characteristics, the values of ideality factor (n) and barrier height (Φb) for the Al/CR/p-Si MIS device were obtained as 1.68 and 0.77 eV, respectively. It was seen that the Φb value of 0.77 eV calculated for the Al/CR/p-Si MIS device was significantly higher than value of 0.50 eV of the conventional Al/p-Si Schottky diodes. Modification of the interfacial potential barrier of the Al/p-Si diode was achieved by using a thin interlayer of the CR organic material. This was attributed to the fact that the CR organic interlayer increased the effective barrier height by influencing the space charge region of Si. The interface-state density of the MIS diode was found to vary from 1.24×1013 to 2.44×1012 eV−1 cm−2.Öğe Yeniçağ da Batılı seyyahların gözüyle Mardin(Batman Üniversitesi, 2012-04) Nasıroğlu Aydın, MehtapÖğe Bir dizel motorunda kanola yağı kullanımında ön-ısıtma işleminin egzoz emisyonlarına etkilerinin deneysel araştırılması(e-Journal of New World Sciences Academy, 2009-03-01) Aydın, Hüseyin; Öner, Cengiz; İlkılıç, Cumali; Hazar, HanbeyBu çalışmanın amacı; bitkisel yağlardan olan kanola yağının önceden ısıtılarak bir dizel motorunda kullanımından kaynaklanan egzoz emisyonlarının nasıl değiştiğini incelemektir. Bu amaçla saf kanola yağı %20 ve %50 oranlarında dizel yakıtı ile karıştırılmış ve bu karışım yakıtlar dört zamanlı, tek silindirli ve hava soğutmalı bir dizel motorda kullanılmıştır. Karışım yakıtlar kullanım sırasında 100o C sıcaklığa kadar ısıtıldıktan sonra kullanılmış ve bu ön ısıtma işleminin dizel motorda ısıl verim, egzoz gazı sıcaklığı, NOx, CO ve duman emisyonlarına etkileri araştırılmıştır. Ön ısıtma işleminin CRO’ nun viskozitesini azalttığı ve daha uygun bir yakıt akışı sağlayarak emisyonlar üzerinde olumlu etki yaptığı sunucuna varılmıştırÖğe Hayvansal yağların dizel motor yakıtı olarak değerlendirilmesi(Taşıt Teknolojileri Elektronik Dergisi (TATED), 2010) Altun, Şehmus; Öner, CengizBiodiesel is an alternative diesel fuel, which is obtained from renewable biological sources such as vegetable oils and animal fats. When biodiesel is produced from food-grade vegetable oils, its the cost increases. To produce biodiesel an economically suitable , its cost must be lowered. The cost of biodiesel can be lowered, when it produces from low-cost feedstocks such as used frying oils and animal fats. Animal fats are highly viscous and mostly in solid form at ambient temperature that they need modifications before using them in diesel engines. The viscosity of animal fats can be reduced using transesterification process, emulsification and pyrolisis. Among these methods, the most commonly used process is transesterification reaction. In this literature review, using animal fat as a fuel for diesel engines is examined.Öğe Electrical properties of organic–ınorganic semiconductor device based on rhodamine-101(SpringerLink, 2009-05) Güllü, Ömer; Turut, Abdulmecit; Yıldırım, Nezir; Çakar, MuzafferRhodamine-101 (Rh101) thin films on n-type Si substrates have been formed by means of evaporation, thus Sn/Rh101/n-Si heterojunctions have been fabricated. The Sn/Rh101/n-Si devices are rectifying. The optical energy gaps have been determined from the absorption spectra in the wavelength range of 400 nm to 700 nm. Rh101 has been characterized by direct optical absorption with an optical edge at 2.05 ± 0.05 eV and by indirect optical absorption with␣an optical edge at 1.80 ± 0.05 eV. It was demonstrated that trap-charge-limited current is the dominant transport mechanism at large forward bias. A␣mobility value of μ = 7.31 × 10−6 cm2 V−1 s−1 for Rh101 has been obtained from the forward-bias current–voltage characteristics.Öğe A study of the rectifying behaviour of aniline green-based Schottky diode(Elsevier, 2010-02) Güllü, Ömer; Aydoğan, ŞakirAn Al/aniline green (AG)/Ga2Te3 device was fabricated and the current–voltage (I–V), capacitance–voltage (C–V) and capacitance–frequency (C–f) characteristics of the device have been investigated at room temperature. The values of the ideality factor, series resistance and barrier height obtained from Cheung and Norde methods were compared, and it was seen that there was an agreement with each other. It was seen that the forward bias current–voltage characteristics at sufficiently large voltages has shown the effect of the series resistance. In addition, it was seen from the C–f characteristics that the values of capacitance have been decreased towards to the high frequencies. The higher values of capacitance at low frequencies were attributed to the excess capacitance resulting from the interface states in equilibrium with the Ga2Te3 that can follow the ac signal.Öğe Fuel properties of biodiesels produced from different feedstocks(Energy Education Science and Technolgy Part A, 2011) Altun, ŞehmusBio diesel is an oxygenated diesel fuel obtained from vegetable oils or animal fats via transesterification reaction. The fuel properties such as viscosity, density, cetane number and heating value are very important for determining the suitability of bio diesel as a diesel engine fuel. These fuel properties mainly depend on the feedstock which is used in the bio diesel production. In this study, the effect of bio diesels produced from different feed stocks such as inedible animal tallow, crude canola oil and canola oil blended with animal tallow on the fuel properties were experimentally investigated. Bio diesel fuels and their blends with petroluem diesel fuel were compared with petroleum diesel (petrodiesel). The results showed that the viscosity and density of all the methyl esters were higher than that of petrodiesel, while the heating values of the methyl esters was lower. Besides, the viscosity and the density of methyl esters are within the bio diesel standards, except for animal tallow methyl ester and it was slightly out of the specification EN 14214. Animal tallow bio diesel has the highest cetane number than those of other fuels include petrodiesel. It is concluded that bio diesels and their blends with petrodiesel have suitable fuel properties, especially cetane numbers, for diesel combustion process.
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